Plant Poisoning foraging

Poisonous plants you should know as a forager

During the period of the Coronavirus lockdown with some food scarcities, the weather generally being good and some people having plenty of time on their hands, interest in foraging has rocketed. One Facebook foraging group has had membership increase by 10,000! I’ve written before (here) about the concerns and positives this brings. Some of the concerns are unfortunately demonstrating themselves repeatedly. This same Facebook group now routinely has 6 – 8 instances each week of people with poisonous plants, examples of them being tasted and very sadly, cases where these have consumed and people hospitalised.

A few “rules” to keep you safe and alive –  you don’t want to be in hospital at the best of times let alone at the moment.

  • Do not taste or eat any plant / berry / fungi unless you are 100% certain it is correctly identified.
  • Use multiple sources to confirm your identification.
  • Some plants and fungi are deadly and can resemble friendly species.
  • Start with safe species that you can definitely recognise.
  • Learn the poisonous species to avoid.
  • “If in doubt leave it out”.

Below are the four poisonous plants that are the most frequent source of problems. This is based on a much longer blog post “Cases of mistaken identity – confusing edible and poisonous plants“.

Hemlock Water Dropwort (Oenanthe crocata)

Toxicity

Hemlock Water Dropwort is frequently described as ‘probably the most poisonous plant found in Britain’. No British wild plant has been responsible for more fatal accidents caused by identification mistakes. The whole plant, especially the roots, is extremely toxic with even a small amount ingested being deadly – you can be dead within 3 hours of consuming it. The mortality rate is quantity dependent but has been reported as between 30%–70%. If you a dog owner do be aware that a significant number of dogs die from eating it too.

The main toxic constituent of Hemlock Water Dropwort is oenanthotoxin.  Symptoms of Hemlock water Dropwort poisoning include nausea, increased salivation, and vomiting. There may be tremor, abdominal cramps, and diarrhoea. Seizures can rapidly develop, blood pressure falls. Acute renal failure has been reported too.

If you come into contact with it wash your hands as soon as possible and avoid touching your eyes and mouth.

 

Identification

Hemlock Water Dropwort and the next plant, Hemlock, are Umbellifers – members of the Carrot or Parsley family. With around 60 family members growing wild in the UK they are notoriously tricky to identify to species level. PEOPLE THAT ARE NEW TO FORAGING SHOULD AVOID FORAGING AND EATING ALL MEMBERS OF THIS FAMILY. The defining feature of plants in this family is that the flowers are in flat-topped or rounded clusters – an umbel.

Note that touching some umbellifers followed by exposure to sunlight, may cause phytophotodermatitis, a serious skin inflammation. Symptoms of which include redness and blistering.

Height: 1 – 1.5 m tall.

Stems: Grooved. Plant entirely hairless.

Flowers: July. Flower diameter c 2 mm. Groups or clusters c 5-10 cm (2 – 4 “) diameter.

Hemlock Water Dropwort Flower - one of the most poisonous plants
Hemlock Water Dropwort Flower. Photo: H. Zell [CC BY-SA 3.0 (https://creativecommons.org/licenses/by-sa/3.0)], via Wikimedia Commons
Leaves: 3-4 times pinnate with toothed wedge-shaped segments. Dark green and look like flat-leaved parsley with a distinctive celery or parsley smell. (Descriptions for umbellifers use the word “pinnate”. This simply means “resembling a feather” having parts or branches arranged on each side of a common axis, in a plant the stem. In a bipinnate (or ‘twice pinnate’ leaf), the leaves are also divided. This idea is extended into 3 or 4 times pinnate).

Leaves of Hemlock Water Dropwort - one of the most poisonous plants
Leaves of Hemlock Water Dropwort

Roots: Distinctive. Cream / White, bunched.

Hemlock Water Dropwort drawing including roots - one of the most poisonous plants
Hemlock Water Dropwort drawing including roots

Habitat

Always found in wet areas such as streams, ditches, wet meadows, marshes, rivers and lakes. Note that following floods, the roots have been washed downstream onto beaches.

Hemlock Water Dropwort - always in or near water - one of the most poisonous plants
Hemlock Water Dropwort – always in or near water.

Edible Plants it might be confused with

The leaves look like flat-leaved Parsley. They can also be confused with other members of the carrot family such as Ground Elder, Alexanders and Common Hogweed as well as cultivated members such as Carrot and Parsnip. The roots known as “dead-man’s fingers” look a bit like cultivated parsnips or the roots of Lesser or Greater Water-Parsnip. The stems have been confused with Celery.

 

Hemlock (Conium maculatum)

Toxicity

Hemlock, like Hemlock Water Dropwort above is another Umbellifer. AGAIN, PEOPLE THAT ARE NEW TO FORAGING SHOULD AVOID FORAGING AND EATING ALL MEMBERS OF THIS FAMILY. It is deadly poisonous with no antidote to the toxins in it. Famously, it was used to put Socrates, and other prisoners, to death in the Ancient World. Chances of recovery increase markedly if it is diagnosed early. The toxins in Hemlock are alkaloids which cause vomiting, headaches, abdominal pain and muscular paralysis, leading to seizures, coma, respiratory failure and eventually death. Only a tiny amount of Hemlock can prove fatal. The toxins can also be absorbed through the skin, so if you come into contact with it wash your hands as soon as possible and avoid touching your eyes and mouth.

 

Identification

Height: 1.5 – 2.5 m tall.

Stems: Thick, smooth green stem, hairless, usually spotted or streaked with red or purple on the lower half of the stem (older plants are spotted).

Leaves: Main leaves twice pinnately divided, broadly feathery. Up to 50 cm long and 40 cm broad.

Hemlock stems and leaves - one of the most poisonous plants
Hemlock stems and leaves. Photo: MPF [CC BY-SA 3.0 (https://creativecommons.org/licenses/by-sa/3.0)]
Smell: “Nasty” – often described as mouse-like, musty or like parsnips.

Flowers: The flowers are small, white, clustered in groups up to 10–15 cm (4 – 6”) across.

Hemlock flowers - one of the most poisonous plants
Hemlock flowers. Photo: Mick Talbot from Lincoln (U.K.), England [CC BY 2.0 (https://creativecommons.org/licenses/by/2.0)] via Wikimedia Commons

Habitat

Mainly wet places – on poorly drained soils, particularly near streams, ditches, and other surface water. Also, on disturbed ground such as roadsides and the edges of cultivated fields.

 

Edible Plants it might be confused with

Leaves look a bit like (cultivated) Parsley or Cow Parsley. The roots like those of Lesser or Greater Water-Parsnip.

 

Lords and Ladies (Arum maculatum)

Lords and Ladies is known by many different names including Cuckoo Pint and Wild Arum.

Toxicity

Consuming the leaves and berries of Lords and Ladies give an immediate burning sensation to lips and throat followed by significant swelling which can result in difficulty breathing.

The berries are one of the most common causes of accidental plant poisoning based on attendance at hospital accident and emergency departments. These are most often consumed by children. Usually the immediate burning in the mouth means they are rarely ingested.

 

Identification

Lords and Ladies (Wild Arum / Cuckoo Pint) - Photo by Sannse, 24 April 2004, Essex, England. One of several commonly confused poisonous plants
Lords and Ladies (Wild Arum / Cuckoo Pint) – Photo by Sannse, 24 April 2004, Essex, England.

Height: Up to 40 cm tall.

Flowers: Chocolate coloured poker-shaped “flower” partially enclosed in a leaf-like hood.

Leaves: A larger leaf is arrow-shaped to triangular and has rounded, backward facing lobes – a bit like an arrow head. Younger leaves do not have the lobes but still have prominent veins. The leaves may have blackish / purple spots.

Lords and Ladies / Cuckoo Pint / Wild Arum leaves. One of several commonly confused poisonous plants
Lords and Ladies leaves at varying stages of growth (light green leaves to near left and right edges of the photograph are another plant).

Berries: In Autumn a cluster of bright red berries

Lords and Ladies berries (Arum maculatum). One of several commonly confused poisonous plants
Lords and Ladies berries (Arum maculatum) – Paul Henderson [CC BY-SA 3.0] via Wikimedia Commons

Habitat

Woodlands, hedgerows, gardens and shady places.

 

Edible Plants it might be confused with

Sorrel. The backwards pointing lobes on Sorrel leaves are pointed (like cut with scissors), on Lords and Ladies they are rounded.  Lords and Ladies leaves also have irregular edges and many deep veins. Sorrel is a plant of grassy fields, Lords and Ladies more shady places.

Sorrel (left) and Lords and Ladies (right)
Sorrel (left) and Lords and Ladies (right). NB Sorrel lobe tips have curled upwards but are V -shaped.

Wild Garlic. Smaller Lords and Ladies leaves can look more like a Wild Garlic leaf, but the veins should still be obvious. They won’t smell of Garlic! Wild Garlic leaves are long, pointed, “spear-shaped”. They do not have veins – just a prominent central mid-rib (looking like an extension of the stalk).

In the below photograph we have – from left to right:

1. Lords and Ladies – rear
2. Lords and Ladies – front
3. Wild Garlic – front
4. Wild Garlic – rear

Leaf comparison - Lords and Ladies and Wild Garlic
Leaf comparison – Lords and Ladies and Wild Garlic (see below).

Dog’s Mercury (Mercurialis perennis)

Toxicity

Symptoms of poisoning from consuming Dog’s Mercury appear within a few hours; they can include vomiting, pain, gastric and kidney inflammation, and sometimes inflammation of the cheeks and jaw and drowsiness. Larger doses cause lethargy, jaundice, painful urination and coma before death.

Identification

Dog's Mercury
Dog’s Mercury

Height: Up to 40 cm tall.

Stems: Downy / hairy

Flowers: Clusters of small cream / green flowers on upright, tassel-like spikes.

Leaves: Spear-shaped, toothed, fresh green leaves

 

Habitat

Woodlands and hedgerows where it can form a dense carpet.

Edible Plants it might be confused with

The main risk is accidentally gathering some when picking Wild Garlic or Nettles which it can grow amongst. Dog’s Mercury has however been confused with Ground Elder and Brooklime, furthermore, it could also be mistaken for a member of the Goosefoot genus.

Dog's Mercury in amongst Nettles
Dog’s Mercury in amongst Nettles

Further reading

Mark Williams of Galloway Wild Foods wrote an excellent article for a magazine on foraging and umbellifers. You can find it here (PDF).

Poisonous Plants in Great Britain by Fred Gillam (book)

The Poison Garden (web site)

Foxglove and other poisonous plants (web site)

 

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